Pregnancy Rates to Fixed Embryo Transfer of Vitrified IVP Bos indicus,Bos taurus or Bos indicus × Bos taurus Embryos

The pregnancy rates obtained after the transfer of cryopreserved in vitro‐produced (IVP) embryos are usually low and/or inconsistent. The objective of this study was to evaluate the pregnancy rates of Holstein, Gyr and Holstein × Gyr cattle after the transfer of vitrified IVP embryos produced with X‐sorted sperm. Seventy‐two Gyr and 703 Holstein females were subjected to ovum pickup (OPU) sessions, followed by in vitro embryo production using semen from sires of the same breeds. Embryos (1636 Holstein, 241 Gyr and 1515 Holstein × Gyr) were exposed to forskolin for 48 h prior to vitrification. The pregnancy rate achieved with Gyr dam and sire was 46.1%, which was similar (p = 0.11) to that of Holstein dam and Gyr sire (40.3%). Crossing Gyr dams with Holstein sires resulted in a pregnancy rate of 38.9% and did not differ (p = 0.58) from the pregnancy rate obtained with the cross between Holstein dams and Gyr sires. The rate obtained with Holstein dam and sire was 32.5%. The average pregnancy rate was 36.6%, and no difference was found in the proportion of female foetuses (88.8%, in average) among breeds (p > 0.05). In conclusion, transfer of cryopreserved X‐sorted embryos represents an interesting choice for dairy cattle. Despite the small differences between pregnancy rates, we highlight the efficiency of this strategy for all of the racial groups studied.     

Efficacy of needle-free injection on antibody production against Clostridium chauvoei in beef calves under field conditions

This study compared needle-free and needle-based injection devices for vaccination of calves against Clostridium chauvoei in warm and cold conditions. Both devices elicited comparable antibody responses in calves. Needle-free injection devices can be used to vaccinate calves provided appropriate precautions are taken in cold weather.     

Increased coniferous needle inputs accelerate decomposition of soil carbon in an old-growth forest

Changes in temperature, precipitation, and atmospheric carbon dioxide (CO₂) concentration that are expected in the coming decades will have profound impacts on terrestrial ecosystem net primary production (NPP). Nearly all models linking forest NPP with soil carbon (C) predict that increased NPP will result in either unchanged or increased soil C storage, and that decreased NPP will result in decreased soil C storage. However, linkages between forest productivity and soil C storage may not be so simple and direct. In an old-growth coniferous forest located in the H.J. Andrews Experimental Forest, OR, USA, we experimentally doubled needle litter inputs, and found that actual soil respiration rates exceeded those expected due to the C added by the extra needles. Here, we estimated that this ‘priming effect’ accounted for 11.5–21.6% of annual CO₂ efflux from litter-amended plots, or an additional 137–256 g C m⁻² yr⁻¹ loss of stored C to the atmosphere. Soil priming was seasonal, with greatest amounts occurring in June–August coincident with peaks in temperature and dry summer conditions. As a result of priming, mineral soil was more resistant to further mineralization during laboratory incubations. Soil lignin-derived phenols in the Double Litter plots were more oxidized than in the control, suggesting that the soil residue was more degraded. Our hypothesis that excess dissolved organic C produced from the added litter provided the link between the forest floor and mineral soil and a substrate for soil priming was not supported. Instead, the rhizosphere, and associated mycorrhizal fungi, likely responded directly to the added aboveground litter inputs. Our results revealed that enhanced NPP may lead to accelerated processing of some stored soil C, but that the effects of increased NPP on ecosystem C storage will be based on a net balance among all ecosystem C pools and are likely to be ecosystem-dependant. Forest C models need to include these complex linkages between forest productivity and soil C storage.     

Phase-matched generation of coherent soft X-rays

Phase-matched harmonic conversion of visible laser light into soft x-rays was demonstrated. The recently developed technique of guided-wave frequency conversion was used to upshift light from 800 nanometers to the range from 17 to 32 nanometers. This process increased the coherent x-ray output by factors of 10(2) to 10(3) compared to the non-phase-matched case. This source uses a small-scale (sub-millijoule) high repetition-rate laser and will enable a wide variety of new experimental investigations in linear and nonlinear x-ray science.     

The role of rituximab in the treatment of canine lymphoma: an ex vivo evaluation

Targeting the CD20 receptor that is common to many B-cell Non-Hodgkin's Lymphoma subtypes in people, rituximab is a chimeric monoclonal antibody which has significantly improved disease-free survival rates compared with the use of cytotoxic agents alone. This study evaluated ex vivo canine B cell binding and depletion by rituximab with flow cytometric technique as possible proof of concept for treatment of canine lymphoma. Despite immunohistochemistry supporting CD20 expression, rituximab did not bind or deplete canine B cells and it is unlikely that it will be added to the armamentarium of treatment options for canine lymphoma.     

Effects of crocin on frozen-thawed sperm apoptosis,protamine expression and membrane lipid oxidation in Yanbian yellow cattle

Glycerol is used as a bovine semen osmotic cryoprotectant that greatly improves the quality of frozen and thawed bovine sperm. However, high glycerol concentrations can have a toxic effect on frozen and thawed bovine sperm. Therefore, this experiment investigated the effect of replacing a portion of the glycerol in a cryoprotectant solution with crocin on the sperm apoptosis, protamine deficiency and membrane lipid oxidation of frozen and thawed Yanbian yellow cattle sperm. The experiment included a control group (6% glycerol) and four treatment groups: I (3% glycerol), II (3% glycerol +0.5 mM crocin), III (3% glycerol + 1 mM crocin) and IV (3% glycerol + 2 mM crocin). Computer assisted semen analysis was used to detect sperm motility, Hoechst 33,342, propidium iodide, and JC-1 staining were used to analyse sperm viability and mitochondrial membrane potential, chromomycin A3 staining was used to detect protamine deficiency and DNA damage, flow cytometry was used for sperm membrane lipid disorder detection and analysis, and real-time quantitative RT-qPCR was used to detect the mRNA expression levels of protamine-related genes (PRM2, PRM3), sperm acrosome-associated genes (SPACA3), oxidative stress-related genes (ROMO1) and apoptosis-related genes (BCL2, BAX). Compared to the control group, replacing a portion of glycerol with 1 mM crocin significantly improved sperm motility, plasma membrane integrity, membrane lipid disorders (p < .05) and viability, mitochondrial membrane potential, protamine deficiency (p < .01). The expression level of PRM2, PRM3, SPACA3 and BCL2 significantly increased (p < .05), while the expression levels of ROMO1 and BAX significantly decreased (p < .05). Accordingly, the BCL2/BAX ratio significantly increased (p < .05). In summary, the substitution of a portion of glycerol with crocin in cryoprotective solution improved the quality of Yanbian yellow cattle sperm after freezing and thawing.     

Isotopic analysis of respired CO2 during decomposition of separated soil organic matter pools

A detailed understanding of the processes that contribute to the δ¹³C value of respired CO₂ is necessary to make links between the isotopic signature of CO₂ efflux from the soil surface and various sources within the soil profile. We used density fractionation to divide soils from two forested sites that are a part of an ongoing detrital manipulation experiment (the Detrital Input and Removal Treatments, or DIRT project) into two soil organic matter pools, each of which contributes differently to total soil CO₂ efflux. In both sites, distinct biological pools resulted from density fractionation; however, our results do not always support the concept that the light fraction is readily decomposable whereas the heavy fraction is recalcitrant. In a laboratory incubation following density fractionation we found that cumulative respiration over the course of the incubation period was greater from the light fraction than from the heavy fraction for the deciduous site, while the opposite was true for the coniferous site.Use of stable isotopes yielded insight as to the nature of the density fractions, with the heavy fraction solids from both forests isotopically enriched relative to those of the light fraction. The isotopic signature of respired CO₂, however, was more complicated. During incubation of the fractions there was an initial isotopic depletion of the respired CO₂ compared to the substrate for both soil fractions from both forests. Over time for both fractions of both soils the respired δ¹³C reflected more closely the initial substrate value; however, the transition from depleted to enriched respiration relative to substrate occurs at a different stage of decomposition depending on site and substrate recalcitrance. We found a relationship between cumulative respiration during the incubation period and the duration of the transition from isotopically depleted to enriched respiration in the coniferous site but not the deciduous site. Our results suggest that a shift in microbial community or to dead microbial biomass as a substrate could be responsible for the transition in the isotopic signature of respired CO₂ during decomposition. It is likely that a combination of organic matter quality and isotopic discrimination by microbes, in addition to differences in microbial community composition, contribute to the isotopic signature of different organic matter fractions. It is apparent that respired δ¹³CO₂ cannot be assumed to be a direct representation of the substrate δ¹³C. Detailed knowledge of the soil characteristics at a particular site is necessary to interpret relationships between the isotopic values of a substrate and respired CO₂.